High frequency generator circuit



Dec. 1, 1931. J, HARRISON 1,834,155

HIGH- FREQUENCY GENERATOR CIRCUIT Filed July 31. 1928 F m i I I I I I'II I INVENTOR. jam/90w 8. fifowmoow,

BY wfl 5 ATTORNEY Patented Dec. 1, 1931 UNITED STATES PATENT OFFICE.

JAMISON R. HARRISON, OE I VIIDDLETO WN, CONNECTICUT HIGH FREQUENCYGENERATOR CIRCUIT Application filed. July 31, 1928. Serial No. 296,584.

arrangements for generating electrical oscillations of constantfrequency.

Another object of my inventionis to provide a balanced vacuumtube'circuit arrangement wherein a plurality of Vacuumtubes may beemployed for producinghigh fre- "quency oscillations of electricalenergy;

Other and further objects of my invention will appearfrom'thespecification to'follow and from the accompanying drawingwherein is illustrated the high frequency generator circuit arrangementof my invention. In the accompanying drawing two electron tubes 1 and 2are represented, each having filament electrodes 3 and 7, inner gridelectrodes 4 and 8, shielding grid electrodes 6 and 10 and plateelectrodes 5 and 9. Filament electrodes 3 and 7 are energizedby source17. Shielding grid electrodes 6 and 10 are supplied with a source ofbiasing energy from source 18 through radio frequency choke coils V 11and 12 respectively. Source of energy 19 supplies a positive potentialto innergrids 4 and 8 and plate electrodes 5 and 9. Radio frequencychoke coil 13excludes radio frequency energy from source 19, Inductance14 and capacity 15 have frequency'characteristics correspondingapproximately to the frequency value of the desired generated frequency. A mechanically vibratile element 16 is employed for maintainingthe circuit at a constant frequency value and has frequencycharacteristics corresponding to the app'roxivarying the couplingbetween the input cir-- 'ing gridt of vacuum tube 1 is supplied withtube '1" will be increasing at the same time that 'ductance coil'14andthe direction of these energy at substantially constant frequencyvalue; An adjustment d provides means for laterally moving conductivemembers A, B withrelation to C, D, andthus varying the phaserelationship between the, two input circuits and two output circuits.

Conductive members-A, B, and Dare connected to electrodes 6, 10, 5-and9respectively. Means are therefore provided for cuit 610 and outputcircuit 5-9. 7

Adjustable contact member 20 provides means for adjusting the relativepositive potential supplied inner grid electrodes and 8; this adjustmentshould be carefully made tosecure satisfactory operation. Shielding grid6 and anode 5 of the electron tube 1 are connected to the conductivemembers A and C respectively which are adj acent to the same face ofthepiezo electric element 16. Likewise the conductive members-B andDadjacent to the opposite side of theelement- 16 are connected to theshielding grid 10 and anode 9 ofelectron tube 2. When a stress is set upin the, element 16 the resulting polarization induces electrical chargesof opposite signon the metallic conductive members adjacent to the twoopposite faces of the element 16.

Conductive members A- and C, when connected to electrodes 6 and 5, willreceive 0 charges of-the same signandlikewise theconductive members Band D will have charges of like sign but which are opposite in sign tothe charges on A andC. When the shieldapositive, potential the shieldinggrid .10 of electron-tube 2 is suppliedwith a. negative potential.Because of these opposite charges, the-current in-the anodecircuit ofelectron 0 thecurrent in the anode-circuit of tube 2 is diminishing.However, anodes 5'and '9 are connected to the opposite ends of the inandoscillations of'highfrequency-electrical energy are maintained by energyfeedback through the vibrating crystal element 16. Conductive members Aand B are the input connections of the feedback circuit and areelectrically connected to shielding grid electrodes 6 and 10 of vacuumtubes 1 and 2 respectively. Shielding grid electrodes 6 and 10 aresupplied with a source of potential from the biasing battery 18 throughthe radio frequency choke coils 11 and 12. Shielding grid electrodes-6and 10 operate as control grid electrodes and inner grid electrodes 4:and8 operate as space charge electrodes. Accordingly the inner gridelectrodes 4 and 8 are supplied with a suitable positive potential fromthe anode supply battery 19. This neutralizes the space charge grideffect around the cathode due to electron emission.

It is obvious that many modifications of the high frequency generatorcircuit of my invention are possible without departing from thespirit ofmy invention and it is to be understood that my invention is not to belimited to the foregoing specification or to the accompanying drawingbut only as defined in the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is as follows:

1. In a balanced electron tube generating system, in combination, twoelectron tubes each having filament, grid, shielding grid and plateelectrodes, a piezo electric crystal element, two pairs of electrodes inelectrical relation with said piezo electric crystal ele- .ment and sopositioned that the electrodes constituting each pair are substantiallyopposite each other and embrace a portion of said piezo electriccrystal, sources of filament and plate potential, input and outputcircuits for each of said tubes, a common load comprising a tappedinductance and a condenser in parallel, a variable intermediate tapconnection for said source of plate potential, said grids beingconnected together and to a tap on said source of plate potential, thepositive terminal of said source of plate potential being connected tothe tapped point of said load inductance, the terminals of said loadinductance being connected respectively to said plate electrodes, saidelectrodes of said piezo electric crystal element being so connectedthat the electrodes constituting one pair are respectively connected tosaid shielding grid electrodes of said tubes, and the electrodesconstituting the other pair are respectively connected to said plateelectrodes of c said tubes.

2. In a system for producing high frequency el ctrical oscillations ofconstant frequency, in combination, two thermionic elecfilaments of saidtubes, a source of plate potential connected to said plates, a source ofpotential for biasing said grid electrodes positively with respect tosaid filament electrodes, a circuit for connecting said grid electrodestogether and to said filament through said source of grid biasingpotential, a source of potential for biasing said shielding gridelectrodes with respect to said filament electrodes, circuits forconnecting said shielding grid electrodes together and to said filamentelectrodes through said source of shielding grid biasing potential,apiezo electric crystal element, two pairs of electrodes for said piezoelectric crystal element, said electrodes being so positioned that theelectrodes constituting each pair are substantially opposite and embracea portion of said crystal and so that said two pairs are spaced fromeach other, circuits connecting the electrodes of one of said pairsrespectively to said shieldmg grid electrodes, and circuits connectingthe electrodes of the other of said pairs respectively to said plateelectrodes.

3. In a balanced electron tube generating system, in combination, aplurality of electron tubes symmetrically arranged in two groups, eachof said tubes having filament, grid, shieldinggrid and plate electrodes,the corresponding electrodes of the tubes composing each of said groupsbeing connected together, a piezo electric crystal element, two pairs ofelectrodes in electrical relation with said piezo electric. crystalelement and so positioned that the electrodes constituting each pair aresubstantially opposite each other and embrace a portion of said piezoelectric crystal, sources of filament and plate potential, input andoutput circuits for each of said tubes, a common load comprising atapped in ductance and a condenser in parallel, a variable intermediatetap connection for said source of plate potential, said grids beingconnected together and to a tap on said source of plate potential, thepositive terminal of said source of plate potential being connected tothe tapped point of said load inductance, the terminals of said loadinductance being connected respectively to the plate electrodes of eachof said groups, said electrodes of said piezo electric crystal elementbeing so connected that theelectrodes constituting one pair arerespectively connected to said groups of shielding grid electrodes ofsaid tubes, and the electrodes constituting the other pair arerespectively connected to said groups of plate electrodes of said tubes.

4. In a balanced electron tube generating system, in combination, aplurality of electron tubes symmetrically arranged in two groups, eachof said tubes having filament, grid, shielding grid and plateelectrodes, the corresponding electrodes of the tubes composing each ofsaid groups being connected to get-her, a piezo electric crystalelement, two

pairs of electrodes in electrical relation with said piezo electriccrystal element and so positioned that the electrodes constituting eachpair are substantially opposite each other and embrace a portion of saidpiezo electric crystal, sources of filament and plate potential, inputand output circuits for each of said tubes, a common load comprising atapped inductance and a condenser in parallel, the positive terminal ofsaid source of plate potentialbeing connectedto the tapped point of saidload inductance, the terminals of said load inductance being connectedrespectively to the plate electrodes of each of said groups, saidelectrodes of said piezo electric crystal element being so connectedthat the electrodes constituting one pair are respectively connected tosaid groups of shielding grid electrodes of said tubes, and theelectrodes constituting the other pair are respectively connected tosaid groups of plate electrodes of said tubes.

5. In a balanced electron tube generating system, in combination, aplurality of electron tubes symmetrically arranged in two groups, eachof said tubes having filament, grid, shielding grid and plateelectrodes, the corresponding electrodes of the tubes composing each ofsaid groups being connected together, a piezo electric crystal element,two pairs of electrodes in electrical relation with said piezo electriccrystal element and so positioned that the electrodes constituting eachpair are substantially opposite each and embrace a portion of said piezoelectric crystal, sources of filament and plate potential, input andoutput circuits for each of said tubes, a common load comprising atapped inductance and a condenser in parallel, a variable intermediatetap connection for said source of plate potential, said grids beingconnected together and to a tap on said source of plate potential, thepositive terminal of said source of plate potential being connected tothe tapped point of said load inductance, the terminals of said loadinductance being connected respectively to the plate electrodes of eachof said groups, means for adjusting the relative spacing of said pairsof electrodes of said piezo electric crystal element, said electrodes ofsaid piezo electric crystal element being so connected that theelectrodes constituting one pair are respectively connected to saidgroups of shielding grid electrodes of said tubes, and the electrodesconstituting the other pair are respectively connected to said groups ofplate electrodes of said tubes.

6. In a balanced electron tube generating system, in combination, aplurality of electron tubes symmetrically arranged in two groups, eachof said tubes having filament, grid, shielding grid and plateelectrodes, the corresponding electrodes of the tubes comaosin each ofsaid rou s bein connected l s together, a mechanically vibratileelement,

two pairs of electrodes in electrical relation with said mechanicallyvibratile element and so positioned that the electrodes constitutingeach pair are susbtantially opposite each other and embrace a portion ofsaid mechanically vibratile element, sources of filament and platepotential, input and output circuits for each of said tubes, a commonload comprising a tapped inductance and a condenser in parallel, avariable intermediate tap connection for said source of plate potential,said grids being connected together and to a ta on said source of platepotential, the posltive terminal of said source of plate potential beingconnected to the tapped point of said load inductance, the terminals ofsaid load inductance being connected respectively to the plateelectrodes of each of said groups, said electrodes of said mechanicallyvibratile element being so connected that the electrodes constitutingone pair are respectively connected to said groups of shielding gridelectrodes of said tubes, and the electrodes constituting the other pairare respectively connected to said groups of plate electrodes of saidtubes.

In testimony whereof I afiix my signature.

JAMISON R. HARRISON.

